This invention relates to a cutting tool using a diamond window.
Diamond is a material which is inert to a variety of hostile environments and also has excellent wear-resistant and abrasive properties, combined with high infra-red transmission. Consequently, it is the ideal material to use in a variety of tools such as laser knives. Laser knives are used in delicate surgical operations and include a tube along which the laser beam is directed ending with a diamond window through which the laser beam passes.
The refractive indices of diamond and air are very different. Consequently, some of the laser beam does not pass through the diamond window and is reflected. The reflected laser beam can cause problems to the handler of the knife and the equipment itself, and diminishes the forward power available.
U.S. Pat. No. 4,383,728 describes a reflector of infra-red radiation comprising a highly reflecting surface coated with a thin infrared transparent layer of glassy diamond-like carbon. The carbon layer may be formed directly on the surface or an initial thin bonding layer, e.g. of silicon or germanium, may be deposited on the reflecting surface followed by the carbon layer.
In an article entitled "The Development of Diamond-like (i-Carbon) Thin Films as Anti-reflecting Coatings for Silicon Solar Cells", 1982, American Vacuum Society, 338 to 340, T. J. Moravec and J. C. Lee describe the application of a diamond-like thin film to silicon as an anti-reflecting coating.